If each cube here represents a pixel, what is the fastest way to change its color so it looks exactly like the 2d image?
This is the fastest way:
1. add a cube
2. add two array modifiers to x and y axis and apply them
3. go to edit mode, use orthagonic view (num5), hit "u" and select "projection from view (boundary)"
4. hit "p" select "by loose parts"
5. go back to object mode, select everything and hit ctrl+shift+alt+c and select "origin to center of mass"